The present invention broadly relates to apparatus for applying staples or wire staples to substantially flat articles or products and, more specifically, pertains to a new and improved apparatus for stapling multipart or multisheet printed products, particularly newspapers, magazines, brochures and the like. The present invention also relates to a new and improved method for stapling printed products in the folded-product delivery of a rotary printed press of machine.
Generally speaking, the stapling apparatus of the present development is of the type for stapling multipart printed products selectively arriving as individual products or in a contiguously joined formation as a multilayered web.
A stitcher for signatures and webs is known from and disclosed in, for example, U.S. Pat. No. 4,315,588 and its corresponding German Patent Application No. 3,203,376, published Aug. 4, 1983. According to this prior art construction, the web or signature sheets to be stapled are guidedly moved between respective cooperating staple-inserting elements and staple-clenching elements. The staple-inserting elements and the staple-clenching elements are carried by respective continuously revolving chain link assemblies having respective runs which extend parallel to the direction of travel of the products and contiguously to the travel pathway of the latter. The staple-inserting elements and the staple-clenching elements located opposite the latter during the stapling operation are synchronously on-line with the signatures during stapling.
A further revolving path formed by male die and transport members mounted at an endless revolving chain link assembly is provided in order to form the staples to be inserted. At the revolving path of these male die and transport members there is arranged a rotary cutter to supply straight cut lengths of wire to the male die and transport members contiguously passing by. The straight cut length of wire is bent or deformed to form a substantially U-shaped staple when the respective male die mates with a female shaping die carried by the contiguously traveling central chain link assembly. In this manner the staple is held in the female shaping die which transports the latter to the stapling zone and acts there as the aforementioned staple-inserting element for ejecting and passing the staple through the oncoming signature, or the like.
This known apparatus for stitching moving paper articles is relatively complicated in construction and design. In this apparatus three adjacent revolving paths defining two contiguous common paths are necessary: one for the magnetic male die members transporting the straight cut lengths of wire; one for the female shaping die members co-acting with the male die members to form the staples and acting as staple-inserting elements to eject and pass the staples through the signatures; and one for clenching male dies acting as the staple-clenching elements. Furthermore, the formed staples are carried and inserted solely in the direction extending in the direction of travel of the signatures.
A simplified construction of the chain drive system of the prior art stitcher as previously explained is disclosed in U.S. Pat. No. 4,792,077. In this known apparatus for applying staples to groups of signatures only two cyclically revolving paths are provided. The two chain link assemblies of these revolving paths have a common contiguous transit path portion which is defined by respective synchronously driven chaindrive sprocket wheel sets. Measured lengths of wire provided by a wire cutter-transfer assembly are supplied to special stapler links carried on one chain link assembly. With this arrangement, the wire feed can be phased to space staples a predetermined number of chain links apart in order to provide staples where desired in a given signature or like paper product. Incoming signatures to be stapled are transferred from an incoming conveyor belt and are grasped between the two sets of links in the respective chains as they contiguously meet. The two revolving chain paths thus assume the double function of inserting the formed staples and conveying the signatures along the contiguous pathway to be discharged onto a suitable conveyor for further transit.
Since the signatures to be staled are delivered with their creases or crease lines aligned with the movement of the links and further conveyed by the cyclically driven chains, the insertion of the staples is accomplished along the respective creases or crease lines in the lengthwise direction of the signatures or like paper products. If a signature is to be provided with two staples, the insertion of the two staples for one signature will be sequentially effected, i.e. one staple after the other.